Antipsychotic drugs are known to alleviate the symptoms of mental illnesses such as schizophrenia. Examples of such drugs include phenothiazine derivatives such as promazine, chlorpromazine, fluphenazine, thioridazine and promethazine, thioxanthenes such as chlorprothixene, butyrophenones such as haloperidol and clozapine. While these agents may be effective in treating schizophrenia, virtually all except clozapine produce extrapyramidal side effects, such as facial tics or tardive dyskinesia. Since antipsychotics may be administered for years or decades to a patient, such pronounced side effects may complicate recovery and further isolate the individual from society.
Compounds having some structural similarity to those of the present invention are described in EPO application 88,309,581.2, U.S. Pat. Nos. 4,772,604; 4,782,061; 4,362,738; 3,988,371; 4,666,924; 4,931,443; and 4,992,441. Other somewhat similar compounds are disclosed in J. Clin. Chem. Clin. Biochem. 1988, 26, 105 and J. Med. Chem., 1991, 34, 2133.
The present invention describes novel compounds that combine antipsychotic effects with minimal or reduced side effects such as extrapyramidal symptomology, and increased acid stability relative to some of the compounds known in the art.